Stinging Nettle Aerial Parts Extract
Also known as: Stinging nettle, nettle leaf, nettle aerial parts extract, Urtica dioica
Overview
Stinging nettle aerial parts extract is derived from the leaves and stems of Urtica dioica, a perennial plant found in Europe, North America, and parts of Asia. Traditionally, it has been used for a variety of conditions, including urinary issues, joint pain, skin conditions, and metabolic disorders. The extract contains bioactive compounds such as flavonoids (quercetin, rutin), phenolic acids (trans-ferulic acid), phytosterols (beta-sitosterol), vitamins, and minerals. Research on stinging nettle is moderate, with a growing number of controlled clinical trials and systematic reviews, particularly for benign prostatic hyperplasia (BPH), metabolic syndrome, and allergic rhinitis. The quality of evidence varies by indication, with some areas supported by robust randomized controlled trials (RCTs) and meta-analyses, while others rely on preclinical or smaller clinical studies.
Benefits
Stinging nettle aerial parts extract offers several evidence-based benefits. For Benign Prostatic Hyperplasia (BPH), systematic reviews and meta-analyses indicate that nettle extract significantly reduces the International Prostate Symptom Score (IPSS), improving urinary symptoms and quality of life. In metabolic syndrome and diabetes, it may enhance insulin secretion and pancreatic β-cell proliferation, contributing to anti-diabetic effects, and contains antioxidants that reduce inflammation and oxidative stress. For allergic rhinitis, clinical studies show antihistamine effects, reducing symptoms like itching and nasal discharge by suppressing histamine release and blocking receptors. Animal studies suggest renal protection, reducing markers of kidney damage and inflammation. Preliminary animal data also indicate potential cognitive benefits, with antioxidant and cortisol-regulating effects that may improve memory and reduce anxiety.
How it works
Stinging nettle aerial parts extract exerts its effects through various mechanisms. Its rich content of flavonoids and phenolic compounds provides potent antioxidant and anti-inflammatory actions. It modulates histamine receptors and inhibits histamine release, which accounts for its antihistamine properties in allergic rhinitis. The extract may enhance insulin secretion and promote pancreatic β-cell proliferation, contributing to its anti-diabetic effects, though the exact pathways are still being investigated. It is also thought to inhibit pro-inflammatory cytokines and oxidative stress mediators, which contributes to its renal and metabolic benefits. The absorption and bioavailability of its active compounds depend on the extraction method, with aqueous and alcoholic extracts commonly used to deliver water-soluble flavonoids and vitamins.
Side effects
Stinging nettle aerial parts extract is generally considered safe, with a low incidence of adverse effects reported in clinical trials. The most common side effects are mild gastrointestinal discomfort, which may include nausea or stomach upset. Allergic reactions are possible but are considered rare. There are no significant drug interactions extensively documented in high-quality studies. However, caution is advised when combining stinging nettle extract with antihypertensive medications, as it may have additive effects on blood pressure. Similarly, individuals taking antidiabetic drugs should monitor blood glucose levels closely due to the extract's potential to affect insulin secretion. Contraindications include pregnancy and lactation, as there is insufficient safety data to recommend its use in these populations. Individuals with known allergies to plants in the Urticaceae family should also avoid its use.
Dosage
Effective doses of stinging nettle aerial parts extract vary depending on the specific extract type and the intended indication. For benign prostatic hyperplasia (BPH), randomized controlled trials have typically used doses ranging from 300 mg to 600 mg of nettle root or aerial parts extract daily. For metabolic and allergic indications, while less standardized, doses often range from 300 mg to 1 gram daily of dried extract or an equivalent amount. Dosing is usually divided and taken with meals to enhance absorption and minimize potential gastrointestinal discomfort. Stinging nettle is available in various forms, including capsules, tinctures, teas, and standardized extracts. Standardized extracts are often preferred as they ensure a consistent concentration of bioactive compounds, which is crucial for predictable efficacy and safety. It is important to follow product-specific dosing instructions or consult a healthcare professional.
FAQs
Is stinging nettle extract effective for urinary symptoms?
Yes, especially in benign prostatic hyperplasia (BPH), where systematic reviews show it significantly reduces symptom scores and improves quality of life.
Can it help with allergies?
Yes, clinical studies demonstrate that stinging nettle extract has antihistamine effects, helping to reduce symptoms like itching, nasal discharge, and tearing.
Is it safe long-term?
Generally, it is considered safe, but long-term safety data are limited. Mild gastrointestinal side effects are the most commonly reported adverse events.
When can I expect to see benefits?
Symptom improvements, particularly for BPH and allergies, often become noticeable within a few weeks of consistent and appropriate use.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC9175978/ – This systematic review and experimental study investigated the antimicrobial activity of nettle extracts. It concluded that there is no strong evidence to support clinically useful antimicrobial activity, primarily based on in vitro studies, highlighting the lack of clinical trials in this area.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC9282742/ – This narrative review focused on the effects of nettle on metabolic syndrome. It summarized findings from various preclinical and clinical studies, indicating that nettle can increase insulin secretion and pancreatic β-cell proliferation, and contains beneficial antioxidants and vitamins, though it noted a limitation in the number of randomized controlled trials.
- https://www.academicpublishers.org/journals/index.php/ijms/article/download/5389/6319/12453 – This systematic review and meta-analysis evaluated the effects of nettle on BPH and other conditions. It found high-quality evidence that nettle reduces IPSS in BPH patients, improves allergic rhinitis symptoms, and showed renal protective effects in animal models, while acknowledging some heterogeneity in extract types and doses across studies.
